1. Field of the Invention
The present invention relates generally to an on-vehicle navigation system using a portable terminal and, in particular, to a cradle for use in such an on-vehicle navigation system.
2. Description of the Related Art
An on-vehicle navigation system is conventionally utilized to provide a variety of traffic information such as geographical information or highway traffic situation required for driving a vehicle in a most efficient manner. Most of those on-vehicle navigation systems are originally installed at some expensive automobiles during their assembly at the automobile factory, or otherwise they may be later installed by automobile accessory shops upon the automobile's delivery from a manufacturer if required by the user.
These on-vehicle navigation systems each include a directional sensor such as a gyro-sensor, acceleration sensor, etc. and a global positioning system (GPS) provided within the vehicle to detect an angle of rotation, velocity or acceleration on a real-time basis during movement of the vehicle, so as to compute a distance of movement of the vehicle or keep track of its position.
However, while those originally installed on-vehicle navigation systems could be used by the users immediately upon the vehicle's delivery, a market product navigation system separately installed by automobile accessory shops and most likely usable in association with a portable telephone terminal should include at least a cradle for fixing the portable terminal, gyro-sensor and acceleration sensor. Such an arrangement may often cause a significant inconvenience to its users upon installation of those navigation systems. Furthermore, for a normal operation of a directional sensor, such as the gyro-sensor, acceleration sensor and so on, its position and installation topology should be kept in a substantially horizontal direction. To meet this requirement, a control unit of the on-vehicle navigational system frequently has been installed within a trunk of the automobile or, in some applications, below a seat assembly, thereby causing inconvenience during its service and/or installation for the user.